Sheet handling device for photocopying machine

ABSTRACT

A device for conveying or positioning and supporting copy sheets for exposure in a photocopying machine is disclosed in which over a top plate is disposed a conveyor belt comprising a plurality of moving belts spaced apart from and in parallel with each other, and a negative pressure chamber formed below the top plate integral therewith is opened at the top plate through an aperture whose length in the longitudinal direction is smaller than the length of the copying sheet of the smallest size used and whose width or length in the transverse direction is substantially equal to that of the copying sheet of the largest size used. Means are provided for automatically defining or changing the effective opening of the aperture depending upon the size of the copying sheet used.

United States Patent Yano et al.

SHEET HANDLING DEVICE FOR PHOTOCOPYING MACHINE Foreign Application Priority Data May 11, 1972 Japan 47-45836 U.S. Cl. 355/73; 355/76; 355/91 Int. Cl. G03b 27/60 Field of Search 355/3, 73, 76, 87, 91

References Cited UNITED STATES PATENTS 1/1966 Muir 248/363 5/l97l Kobayashi.. 355/91 8/l972 355/87 July 8, 1975 {57] ABSTRACT A device for conveying or positioning and supporting copy sheets for exposure in a photocopying machine is disclosed in which over a top plate is disposed a conveyor belt comprising a plurality of moving belts spaced apart from and in parallel with each other, and a negative pressure chamber formed below the top plate integral therewith is opened at the top plate through an aperture whose length in the longitudinal direction is smaller than the length of the copying sheet of the smallest size used and whose width or length in the transverse direction is substantially equal to that of the copying sheet of the largest size used, Means are provided for automatically defining or changing the effective opening of the aperture depending upon the size of the copying sheet used.

3 Claims, 7 Drawing Figures WWW 8 1975 3.893; 765

SHEET HANDLING DEVICE FOR PHOTOCOPYING MACHINE BACKGROUND OF THE INVENTION The present invention relates generally to a photocopying machine and more particularly to a device for handling (i.e. positioning and supporting) copy sheets for exposure in a photocopying machine, such device including a top plate with a rectangular aperture of variable size.

In general. mechanisms for handling or positioning and supporting a copy sheet for exposure in a photo copying machine, include a conveyor belt generally comprising a plurality of moving belts spaced apart from and in parallel with each other, and a top plate having a plurality of suction holes formed in rows there-through in parallel with the moving belts and communicating with a negative pressure chamber formed below the top plate, and integral therewith. The negative pressure chamber communicates with a suction device such as an electric fan through a suction port formed through a side wall thereof. However the number of effective suction ports varies depending upon the size of a copying sheet placed upon and transported by the conveyor belt so that the load of the fan motor varies over a wide range, thus leading to damage thereto. Furthermore the suction forces are smaller as the size of the copying sheet is smaller so that the copying sheet is not transported along a predetermined path. Therefore wrinkles are formed and the image is not formed in a desired or correct relation with the copying sheet.

SUMMARY OF THE INVENTION One of the objects of the present invention is therefore to provide a device for handling or positioning and supporting a copy sheet for exposure in a photocopying machine, which device may hold the copying sheet in correct position and maintain it completely flat during the exposure process under uniform suction forces.

Briefly stated, according to the present invention a conveyor belt comprising a plurality of moving belts spaced apart from and in parallel with each other is disposed upon a top or exposure plate of the sheethandling device. A negative pressure chamber formed below the top or exposure plate integral therewith opens at the upper surface of the top plate through an aperture whose length in the longitudinal direction is smaller than the length of the copying sheet of smallest size used and whose transverse length or width is substantially equal to the width of the copying sheet of largest size used. Furthermore means are provided for automatically defining or changing the effective opening of the aperture of the top plate depending upon the sizes of the copying sheets used.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a sheet-handling device in accordance with the present invention;

FIG. 2 is a sectional view taken along the line I-I of FIG. 1;

FIG. 3 is a view illustrating a device for automatically changing the effective opening of an aperture ofa negative pressure chamber;

FIG. 4 is a fragmentary view, on enlarged scale thereof;

FIG. 5 is a sectional view taken along the line Il-ll of FIG. 4',

FIG. 6 is a perspective view illustrating the pressure chamber, its aperture and some components of the device for changing the effective opening of the aperture; and

Flg. 7 is a view illustrating a variation of the device for changing the effective opening of the aperture shown in FIGS. 3, 4, 5 and 6.

DESCRIPTION OF THE PREFERRED EMBODIMENTS:

Referring to FIGS. 1 and 2, a conveyor belt generally indicated by 1 comprises a plurality of round moving belts which are transversely spaced apart from and in parallel with each other. An aperture 2a, which is formed through a top plate 2c, has a longitudinal length smaller than that of a copying sheet of the minimum size and a transverse length or width substantially equal to the width of a copying sheet of the maximum size. The aperture 20 communicates with a negative pressure or suction chamber 2 formed integral with the undersurface of the top plate 2c and provided with a discharge port 2b formed through one side wall for communication with a section device (not shown). The conveyor belt 1 is wrapped around a driving roller 3, which is disposed at one end of a sheet-handling device and is driven by a motor (not shown), and three guide rollers 4a, 4b and 4c, the guide roller 40 being disposed at the other end of the sheet-handling device and the guide rollers 4b and 4c being respectively disposed on opposite sides of the negative pressure chamber 2.

A copying sheet A, which is placed upon and transported by the conveyor belt I, is pressed against it by air flows flowing in the directions indicated by the arrows in FIG. 2 so that the copying sheet A may be prevented from being displaced from a correct position.

Next referring to FIGS. 3, 4 and 5, a device for changing the flow rate of air depending upon the size of copying sheets will be described. Reference numerals S designate crank levers pivoted with a connecting rod 6 and a pivot pin 6' to one side wall of the negative pressure chamber 2 and joined to cam levers 7 and 7. Flaps 8 and 8' are pivotably fixed to the top plate 20 with hinges 9 and 9', respectively, and have leaf springs 10 and 10' fixed to the undersurfaces thereof. The free ends of the cam levers 7 and 7' engage with the leaf springs 10 and 10' and when the crank levers '7 and 7' are in upright position the flaps 8 and 8' are raised in common plane relation with the top plate 2c as best shown in FIGS. 4 and 5. A contact lever ll fixed to the end of the connecting rod 6 remote from the crank lever 5 is so biased as to normally rotate in the clockwise direction under the force of a spring 12 loaded between the contact lever 11 and a stationary member such as the top plate 2:. When a rolled copying sheet is used, the contact lever ll engages with a flange A, of a spool of a rolled copying sheet as best shown in FIG. 3. The crank levers 5 and 5' are interconnected by a connecting lever 13 as best shown in FIG. 3 so that they may rotate through the same angle. A stop 14 is provided in order to limit the clockwise rotation of the flap 8'.

Next the mode of operation will be described when copying sheets of two different sizes are used. When a larger-size rolled copying sheet is used, the contact lever 11 engages with the flange A as indicated by the solid lines in FIG. 3 so that the cam levers 7 and 7' are rotated and the flaps 8 and 8 are located in the inclined positions indicated by the solid lines in FIG. 3 under their own weights and the negative pressure in the chamber 2. As a result the effective opened area of the aperture 2a of the negative pressure chamber 2 becomes large so that substantially the whole surface of the copying sheet A may be securely pressed against the conveyor belt I by the suction forces produced by the negative pressure.

When the smaller-size rolled copying sheet with a flange A indicated by the phantom lines in FIG. 3 is used, the contact lever 11 rotates in the clockwise direction under the force of the spring 12 so that the cam levers 7 and 7 are brought to the upright position. The free ends of the cam levers 7 and 7' raise the flaps 8 and 8' through their leaf springs 9 and 9' into the common plane relation with the top plate 2c and the side edges of the flaps 8 and 8' air-tightly engage with the undersurface of the top plate 2c. As a result the actual passage of the aperture 20 is reduced so as to correspond to the width of the smaller-size copying sheet so that the copying sheet may be also effectively pressed against the conveyor belt 1.

Next referring to FIG. 7, there is shown a device for varying the effective opening of the aperture 20 depending upon more than three different sizes of copying sheets. The contact lever 11' and the crank lever are fixed to the connecting rod 6" rotatably supported by one side wall of the negative pressure chamber 2. Tl-Ie crank lever S" is biased under the force ofa spring 12' so as to normally rotate in the clockwise direction. Driving levers 7" and 7" are connected at first ends thereof to the crank lever 5" through the connecting levers l3 and 13'' and provided with pins 7a" and 70" formed at the other ends thereof. A pair of sliding plates 8" and 8", which are adapted to move toward and away from each other so as to define the opening of the aperture 2a, are provided with depending members having elongated slots 8a" and Sa' into which are loosely fitted the pins 7a" and 7a', respectively.

Next the mode of operation will be described. When the contact lever 11' is engaged with the flange A," of the medium-size rolled copying sheet, the sliding plates 8" and 8" are moved toward each other to the positions indicated by the solid lines in FIG. 7, thereby defining the opening of the aperture 2a. However when the contact lever Il' engages with the flange A of the large-sized copying sheet roll, the connecting rod 6" is rotated in the counterclockwise direction, and the sliding plates 8" and 8" are moved away from each other to the positions indicated by the two-dash chain lines in FIG. 7 so that the aperture 2a may be fully wide opened. When the contact lever 11" engages with the flange A, of the small-size copying sheet roll, the sliding plates 8" and 8" are fully advanced to each other into the positions indicated by the broken lines in FIG. 7, thereby defining the smaller opening of the aperture 20. Therefore it is seen that the opening or air passage of the aperture may be automatically controlled in response to the size of the rolled copying sheet used.

In the instant embodiment, the automatic opening control device has been described as defining only three openings of the aperture 2a, but it will be understood that it may also control the sliding plates 8" and 8" so as to define a plurality of openings depending upon the sizes of the rolled copying sheets when the configuration of the contact lever 11' is suitably selected.

As described hereinbefore according to the present invention, the optimum opening or width of the aperture of the negative pressure chamber may be automatically controlled depending upon the sizes of the copying sheets used so that the copying sheet may be at tracted and pressed against the conveyor belt I by the stable and uniform negative pressure. Furthermore the air flows through the space between the copying sheet and the top plate so that the pressure acting upon the copying sheet may be suitably controlled. Therefore the flatness of the copying sheet on the conveyor belt may be maintained in a very satisfactory manner. Since the change in air flow rate due to the different sizes of copying sheets used is small, the variation in load of a fan motor is also small so that the efficiency of a fan may be considerably improved. Thus the present invention provides an efficient but inexpensive device for positioning and supporting copy sheets for exposure in a photocopying machine.

What is claimed is:

l. A device for positioning and supporting copy sheets for exposure in a photocopying machine comprising a. a conveyor belt comprising a plurality of belts which are spaced apart from and in parallel with each other on said device and moved in the longitudinal direction of said device,

b. a top plate provided with an aperture whose longi tudinal length is smaller than the length of the smallest-sized copy sheet used and whose transverse length or width is substantially equal to that of the largest-sized copy sheet used,

c. a negative pressure chamber formed below said top plate integral therewith and opened at the upper surface of said top plate through said aperture thereof, whereby a copy sheet placed upon said conveyor belt may be attracted and pressed thereupon by the difference pressure between atmospheric pressure and negative pressure produced in said negative pressure chamber, and air flows flowing in the longitudinal direction of said device may be formed between the copy sheet upon said conveyor belt and said top plate due to the difference between the atmospheric pressure and said negative pressure to prevent production of local, excessive suction forces, thereby maintaining the flatness of the exposure plane regardless of the sizes of copy sheets used,

d. flaps disposed in said aperture of said top plate for controlling the opening of said aperture,

e. a contact lever adapted to engage with a flange of a spool of a rolled copy sheet loaded in the photocopying machine so as to be rotated depending upon the size thereof, and

f. cam levers operatively coupled to said contact lever for controlling the movement of said flaps in response to the angle of rotation of said contact lever, whereby the effective opening of said aperture may be automatically controlled in response to the size of a rolled copy sheet used.

2. A device for positioning and supporting copy sheets for exposure in a photocopying machine comprising a. a conveyor belt comprising a plurality of belts which are spaced apart from and in parallel with each other on said device and moved in the longitudinal direction of said device,

b a top plate provided with an aperture whose longitudinal length is smaller than the length of the smallest-sized copy sheet used and whose transverse length or width is substantially equal to that of the largest-sized copy sheet used,

c. a negative pressure chamber formed below said top plate integral therewith and opened at the upper surface of said top plate through said aperture thereof, whereby a copy sheet placed upon said conveyor belt may be attracted and pressed thereupon by the difference pressure between atmospheric pressure and negative pressure produced in said negative pressure chamber, and air flows flowing in the longitudinal direction of said device may be formed between the copy sheet upon said conveyor belt and said top plate due to the difference between the atmospheric pressure and said negative pressure to prevent production of local, excessive suction forces, thereby maintaining the flatness of the exposure plane regardless of the sizes of copy sheets used.

d. sliding plates disposed immediately beneath said top plate for controlling the opening of said aperture,

e. a contact lever adapted to engage with a flange of a spool of a rolled copy sheet loaded in the photocopying machine so as to be rotated depending upon the size thereof, and

f. cam levers operatively coupled to said contact lever for controlling the movement of said sliding plates in response of the angle of rotation of said contact lever, whereby the effective opening of said aperture may be automatically controlled in response to the size of a rolled copying sheet used.

3. A device for positioning and supporting copy sheets for exposure in a photocopying machine, comprising a. conveyor means including a plurality of spaced parallel belts for advancing a copy sheet in a given direction;

b. a plate over which said belts are trained. said plate having an aperture with a dimension in said given direction shorter than the length of the smallestsized copy sheet used and a dimension transverse to said given direction substantially equal to the width of the largest-sized copy sheet used;

c. a negative pressure chamber disposed beneath said plate and opening upwardly through said aperture for attracting and holding a copy sheet advanced by said conveyor means over said aperture;

(1. means for partially occluding at least one side portion of said aperture to vary the effective transverse dimension of said aperture, said occluding means comprising at least one member movable into and out of a position occluding a side portion of said aperture; and

e. means for controlling said occluding means, to vary the effective transverse dimension thereof, in accordance with the size of copy sheet material disposed for advance on said conveyor means;

f. said controlling means comprising an element movable between at least two positions in correspondence with different copy sheet widths, and means operatively connecting said element to said member such that the position of said member is determined by the position of said element; and

g. said movable element being positioned to engage a flange of a spool of copy sheet material loaded in the photocopying machine, so as to be moved between said positions depending on the size of said spool 

1. A device for positioning and supporting copy sheets for exposure in a photocopying machine comprising a. a conveyor belt comprising a plurality of belts which are spaced apart from and in parallel with each other on said device and moved in the longitudinal direction of said device, b. a top plate provided with an aperture whose longitudinal length is smaller than the length of the smallest-sized copy sheet used and whose transverse length or width is substantially equal to that of the largest-sized copy sheet used, c. a negative pressure chamber formed below said top plate integral therewith and opened at the upper surface of said top plate through said aperture thereof, whereby a copy sheet placed upon said conveyor belt may be attracted and pressed thereupon by the difference pressure between atmospheric pressure and negative pressure produced in said negative pressure chamber, and air flows flowing in the longitudinal direction of said device may be formed between the copy sheet upon said conveyor belt and said top plate due to the difference between the atmospheric pressure and said negative pressure to prevent production of local, excessive suction forces, thereby maintaining the flatness of the exposure plane regardless of the sizes of copy sheets used, d. flaps disposed in said aperture of said top plate for controlling the opening of said aperture, e. a contact lever adapted to engage with a flange of a spool of a rolled copy sheet loaded in the photocopying machine so as to be rotated depending upon the size thereof, and f. cam levers operatively coupled to said contact lever for controlling the movement of said flaps in response to the angle of rotation of said contact lever, whereby the effective opening of said aperture may be automatically controlled in response to the size of a rolled copy sheet used.
 2. A device for positioning and supporting copy sheets for exposure in a photocopying machine comprising a. a conveyor belt comprising a plurality of belts which are spaced apart from and in parallel with each other on said device and moved in the longitudinal direction of said device, b. a top plate provided with an aperture whose longitudinal length is smaller than the length of the smallest-sized copy sheet used and whose transverse length or width is substantially equal to that of the largest-sized copy sheet used, c. a negative pressure chamber formed below said top plate integral therewith and opened at the upper surface of said top plate through said aperture thereof, whereby a copy sheet placed upon said conveyor belt may be attracted and pressed thereupon by the difference pressure between atmospheric pressure and negative pressure produced in said negative pressure chamber, and air flows flowing in the longitudinal direction of said device may be formed between the copy sheet upon said conveyor belt and said top plate due to the difference between the atmospheric pressure and said negative pressure to prevent production of local, excessive suction forces, thereby maintaining the flatness of the exposure plane regardless of the sizes of copy sheets used, d. sliding plates disposed immediately beneath said top plate for controlling the opening of said aperture, e. a contact lever adapted to engage with a flange of a spool of a rolled copy sheet loaded in the photocopying machine so as to be rotated depending upon the size thereof, and f. cam levers operatively coupled to said contact lever for controlling the movement of said sliding plates in response of the angle of rotation of said contact lever, whereby the effective opening of said aperture may be automatically controlled in response to the size of a rolled copying sheet used.
 3. A device for positioning and supporting copy sheets for exposure in a photocopying machine, comprising a. conveyor means including a plurality of spaced parallel belts for advancing a copy sheet in a given direction; b. a plate over which said belts are trained, said plate having an aperture with a dimension in said given direction shorter than the length of the smallest-sized copy sheet used and a dimension transverse to said given direction substantially equal to the width of the largest-sized copy sheet used; c. a negative pressure chamber disposed beneath said plate and opening upwardly through said aperture for attracting and holding a copy sheet advanced by said conveyor means over said aperture; d. means for partially occluding at least one side portion of said aperture to vary the effective transverse dimension of said aperture, said occluding means comprising at least one member movable into and out of a position occluding a side portion of said aperture; and e. means for controlling said occluding means, to vary the effective transverse dimension thereof, in accordance with the size of copy sheet material disposed for advance on said conveyor means; f. said controlling means comprising an element movable between at least two positions in correspondence with different copy sheet widths, and means operatively connecting said element to said member such that the position of said member is determined by the position of said element; and g. said movable element being positioned to engage a flange of a spool of copy sheet material loaded in the photocopying machine, so as to be moved between said positions depending on the size of said spool. 